Police are investigating the man behind the vicious stabbing attack that occurred in Brooklyn on Saturday, leaving a mother and her four children dead, the Detroit Free Press reported.

Mingdong Chen, 25, was arrested and faces five counts of murder of his cousin's wife and children after stabbing them to death in their Sunset Park home.

You can see a picture of Chen here.

Two girls, Linda Zhou, 9, Amy Zhou, 7, and the youngest son, William Zhou, 1, were pronounced dead at the home. Their brother, Kevin Zhou, 5, and the mother, Qiao Zhen Li, 37, were rushed to the hospital where they were eventually pronounced dead as well. 

NYPD Chief of Department Philip Banks III said all five victims "were cut and butchered with a kitchen knife" in the neck and torso areas. 

"It's a scene you'll never forget," Banks said.

Chen was staying with his cousin's family for about a week and was unemployed. Though he had immigrated to the U.S. over a decade ago, he was still only fluent in Mandarin and expressed that he was jealous of the success of fellow immigrants.

"He made a very soft comment that since he came to this country, everybody seems to be doing better than him," Banks added.

According to police, the mother was reportedly alarmed at Chen's "suspicious" behavior. When she called her husband and mother-in-law about her concern, her mother-in-law sent her daughter and son-in-law, who live in the same neighborhood, to go check on her and the kids.

When her sister-in-law and husband arrived at the apartment, Chen opened the door to the crime scene, covered in blood.

A neighbor of the family, Bob Madden, said he saw a man being taken out of the building by police and was "staring, he was expressionless."

May Chan, another neighbor, said the father was told what happened through the help of a Chinese interpreter.

"The father was freaking out," said Chan. "He just came home from work and saw the police and they told him. He was hysterical."